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Thanks! I tried to make it a true cinematographers still life. There are some cool gems I've collected over the years in that still life. Off the top of my head, an original 1922 American Cinematographer magazine, every American Cinematographer magazine during World War II, and a 1930 Cinematographic Annual (the 1st and earliest precursor of the American Cinematographer's Handbook) that belonged to Clyde DeVinna, ASC... the second cinematographer to ever win an Academy Award for Best Cinematography, and the first to do it solo (the first Oscar went to two cinematographers).

Last edited by Ryan Patrick O'Hara; 01-18-2011 at 10:57 PM.

If cinematography wasn't infinite, I'm sure I would have found the end by now.

Am I completely blind? That still camera has a strange blue halo, the letters are fringing and something funky is going on in that pistol grip.
Looks like chromatic aberration to me, but who knows, maybe it´s the chip, Bayern pattern and codec.

Chromatic aberration can be both axial (longitudinal), in that different wavelengths are focused at a different distance from the lens, different points on the optical axis (focus shift); and transverse (lateral), in that different wavelengths are focused at different positions in the focal plane (because the magnification of the lens also varies with wavelength; indicated in graphs as (change in) focus length). The acronym LCA is used, but ambiguous, and may refer to either longitudinal or lateral CA; for clarity, this article uses "axial" (shift in the direction of the optical axis) and "transverse" (shift perpendicular to the optical axis, in the plane of the sensor or film).

These two types have different characteristics, and may occur together. Axial CA occurs throughout the image, and is reduced by stopping down (this increases depth of field, so though the different wavelength focus at different distances, they are still in acceptable focus). Transverse CA does not occur in the center, and increases towards the edge, but is not affected by stopping down.

In digital sensors, axial CA results in the red and blue planes being defocused (assuming that the green plane is in focus), which is relatively difficult to remedy in post-processing, while transverse CA results in the red, green, and blue planes being at different magnifications (magnification changing along radii, as in geometric distortion), and can be corrected by scaling the planes appropriately so they line up. http://en.wikipedia.org/wiki/Chromatic_aberration

Am I completely blind? That still camera has a strange blue halo, the letters are fringing and something funky is going on in that pistol grip.
Looks like chromatic aberration to me, but who knows, maybe it´s the chip, Bayern pattern and codec.

I would be happy to examine these things you are discussing, but I must say it would be very very helpful if you would give a reference to which images you are examining.

With that said, I never went through these images thoroughly for aberration, as this test was for color matching and contrast. However, I have looked into it, and you have found some very interesting things worth mentioning.

Out of the examples you gave, and I mean no offense, I only think the image of the Yashica camera is worth examining. I would be happy to take a look at the other examples should you give me an image you are looking at. So far those other images look like very very zoomed in images portraying what looks like random noise in the image. It's kinda funny that it appears the arrows you added to the image has spawned more of the noise around them. Perhaps a culprit of compression, the camera sensor, who knows. I don't think this has anything to do with the lens, quite frankly, but I would be happy to revisit it if I find this is more than just super enlarged imaging.

Ok, so back to the Yashica camera. From the image you posted, I must say you have found what I consider an usual suspect of chromatic aberration. I don't know what you were talking about, but I assume it's the same. Anyhow, despite not specifying which image you pulled the still from, luckily the Yashica camera is one of the outer-most props on the table, isolating your image from either the 18mm or 25mm FoV's. It should be noted that chromatic aberration is often found in focal lengths with wide field of views and near the peripheral of that FoV. Thus it seems our culprit fits the bill. Considering the above.

So let's examine two areas of the images, first with the Yashica camera. I took the 8bit .jpg images available in this thread, enlarged greatly, and used mac's Shift+Apple+4 to screen capture a .png file. I assume this is not a loss-less process, but chromatic aberration cannot be caused by this process, so please, for now, disregard what may have been an increase in pixel compression. If we want to explore that at another time, I'll do it correctly.

Please remember that the two enlarged images following the one below, are just portions of this 4k... please note the scale of the object as to understand how much chromatic aberration is taking place. The Yashica camera has been colored Red to show you how much we are zooming into the still frame from the video. If my math is right, the full image is about 32x larger than the portion we are about to examine!

25mm**Next is the 25mm focal lengths. The following image is the FoV of the 25mm, with the Yashica camera highlighted in red, so you can understand the scale of how zoomed in we are looking and the offset of the chroma aberration.**

Enlarged from Cooke CXX T/2 15-40mm zoom lens at 25mm T/2.8:

Enlarged from Cooke Panchro/i 25mm T/2.8 wide open:

Conclusion from Yashica camera analysis:(as it happens, if you only looked at the 'checkered' comparison files I offered in this thread, the Yashica camera was always in the lower right quadrant, which was always designated as the CXX. So I suppose it would have been impossible to see how the Panchro/i's handled aberration on the Yashica, unless you explored their .jpg stand-alone image.)

Postmaster has brought to light some images which have spurred me to dig deep into these images. It appears that the CXX-zoom does have considerably more aberration than the Panchro/i's when you really explore the image. This was a little shocking, as far as how much the CXX produced but upon further contemplation, it wasn't as surprising. As mentioned above, chromatic aberration is the offset of wavelengths of light (in most cases the blue-violet wavelengths (the shortest in our visible spectrum)) and lenses succumb to aberration increasingly so when bending light from very off-parallel angles, such as the peripheral of wide FoV's. Also, I believe that the more optical elements within a lens, the more difficult it becomes to properly bend the wavelengths of light correctly, meaning it's no surprise to me that an ultra wide 2.67:1 zoom (starting at 15mm and T/2) has more aberration than a prime lens which has considerably less optical elements. Looking at the CXX aberration now, it's definitely more than most DP's would like to see, but given the fact it's a 15mm-40mm zoom lens, the complexity of the lens and how it exists in the realm of chromatic aberration optimal conditions, I'd be interested to know if anyone could find a better ultra wide-angle zoom lens with no aberration. I guess that's being fair to a $38,500 zoom (or so says ebay).

Now examining the 25mm, we still see the CXX has much more aberration than the Panchro/i. The Panchro/i 25mm does pick up a little, because now, with the tighter focal length, the Yashica camera is on the very very edge of the FoV. This means the light coming from the Yashica camera is entering the lens at the most extreme angle opposed to the parallel light entering from straight ahead. Thus the light rays are bent to near perfection. It's there on the very fringe, but look at the variables. We are unforgiving zoomed into a 4k file by over 32x magnification on the edges of a wide lens. At this level, I'm certainly not concerned nor do I think they are performing outside the tolerances of what we expect from top pro-lenses.

Sadly, we did not have any S4/i primes in the wide variety, so I cannot test those results. Just the CXX v. Panchro/i.

It's not perfect, but I don't think they are fringing like mad, not the Panchro/i's certainly, and not quite the CXX. I do agree, now that I have examined the CXX, that it does have considerably more aberration than it's Cooke panchro/i brothers, but as mentioned, the lens is practically built to be prone to aberration, I consider the amount there is as a valiant battle of suppression. Show me a 15mm zoom lens that does better, and perhaps I'll start to shame Cooke and their CXX. There's definitely some there mate. I give you that.

The original review pointed out the CXX had a slightly less 'flat-field' perspective. Probably also why it has more aberration than the primes? I bet so.

What do you think? Take a look at the 'Arri' hat, and you'll see the same results.

Last edited by Ryan Patrick O'Hara; 01-19-2011 at 05:26 AM.

If cinematography wasn't infinite, I'm sure I would have found the end by now.